Hadi Eskandari Damaneh; Hamid Gholami; Rasool Mahdavi; Asad Khoorani; Junran Li
Abstract
In this study, water use efficiency index (WUE) was used to assessing the effect of drought on the carbon and water cycle. To calculate this index, we used the gross primary product (GPP) and evapotranspiration (ET) products obtained from the MODIS sensor, and the trend of their changes and reaction ...
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In this study, water use efficiency index (WUE) was used to assessing the effect of drought on the carbon and water cycle. To calculate this index, we used the gross primary product (GPP) and evapotranspiration (ET) products obtained from the MODIS sensor, and the trend of their changes and reaction of this index to drought were calculated for the period 2017-2001 in Fars province. Finally, we assessed the land degradation and desertification in different land uses for study area. The results showed that the indices of evapotranspiration, GPP, water use efficiency, and drought increased by 75.25%, 29.9%, 78.51%, and 67.23%, respectively. The effects of drought on evapotranspiration in agricultural lands and grasslands showed more than 67% positive relationship and also, in these land uses, we observed a significant positive relationship (33.4% and 12.5% for the agricultural lands and grassland, respectively). However, in shrubs lands, and savannas, it is more than 66.6% and 87.5%. The effect of drought on water use efficiency in grassland showed that more than 87% of these areas have a positive relationship. The effectiveness of water use efficiency in plants shows a positive relationship in 40.9% in this area, of which only 0.9% has a significant positive relationship. The negative relationship of this land use is about 59.1% of it. Of this negative amount, only 1.6% of the area had a significant negative relationship. The study of this relationship in the use of savannas shows 75% of this area, which includes 1.5 square kilometers.
Sayyed Alireza Hosseini; Hassan Khosravi; Hamid Gholami; Yahya Esmaeilpour; Artemi Cerda
Abstract
In this study, land use change trend in coastal areas of south of Iran, including Sistan Baluchestan, Hormozgan, Bushehr were studied during 31 years (1988-2019). Landsat satellite images including TM, ETM +, OLI were used for this purpose. The maximum likelihood method was also used to classify satellite ...
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In this study, land use change trend in coastal areas of south of Iran, including Sistan Baluchestan, Hormozgan, Bushehr were studied during 31 years (1988-2019). Landsat satellite images including TM, ETM +, OLI were used for this purpose. The maximum likelihood method was also used to classify satellite images. Vegetation indices (SAVI) and salinity index (SI1) were used to influence land use classes on land degradation and desertification. The results of land use change trend showed that Changes in land use classes of man-made areas and saline lands as the most dynamic land use classes followed an increasing trend of 2.72% and 1.14%, respectively. The results of multivariate regression analysis showed that three vegetation, saline and man-made variables, and four vegetation, saline, man-made and sandy areas explain 22.3% and 37.8% of the dependent variables of vegetation and salinity indices, respectively. Therefore, in more than 60% of changes, other environmental variables are affected. Hence, with respect to the results of land use area and regression analysis and the mean trend of SAVI and SI1 changes, where vegetation and SAVI classes show decreasing trend and saline land and SI1 classes have increasing trend, it can be concluded that land use changes is phenomena that changes ecosystem services with almost irreversible impacts. This will have nothing to do with disturbing the ecosystem balance and intensifying land degradation in coastal areas.
Gholamreza Zehtabian; Hassan Khosravi; Ali Azareh
Abstract
Need to Increasing agricultural land in order to improve food resources in the past two centuries recentlead to widespread changes in land use and improper management of these lands. Continue thisprocess can lead to land degradation and desertification, and improve such soils is very costly;Therefore, ...
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Need to Increasing agricultural land in order to improve food resources in the past two centuries recentlead to widespread changes in land use and improper management of these lands. Continue thisprocess can lead to land degradation and desertification, and improve such soils is very costly;Therefore, prevention of land degradation is more desirable. This function requires to research on theutilization of land agricultural and how to use. With this aim, the Khatam city was selected as thestudy region and various maps of the region, including soil, land use and height maps was prepared tohelp ArcGIS9.3 and ENVI software. Four dominant land region mention mono cultivated and multicultivated systems under irrigation, garden lands and range lands as control treatments wereconsidered as the treatments. The soil was sampled and soil factors in two corrective factors, includingcorrection factors N, P, K, CO, Caco3, Mg and damaging factors Hco3, Cl, Na, pH, EC and SAR atdepth 0 to 30 cm of the soil surface horizons were studied. Factors the design of split plots showed thatthere are significant differences between treatments in the region and soil of region is relatively poorfrom CO, N, K and P in soils Rdhy. The comparison of treatment means with Duncan MeanComparison indicated that the garden lands as the most suitable treatments and range lands as the mostunsuitable one.
M. Navidi; F. Sarmadian; Sh. Mahmoudi
Volume 62, Issue 2 , October 2009, , Pages 299-309
Abstract
Sustainable exploitation of land resources is directly affected by considering soil quality which finally will also conclude environmental protection. Therefore, assessing different soil quality aspects which are sensitive to various land management practices seems too important. In this study, some ...
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Sustainable exploitation of land resources is directly affected by considering soil quality which finally will also conclude environmental protection. Therefore, assessing different soil quality aspects which are sensitive to various land management practices seems too important. In this study, some selected soil quality indicators have been compared in five land use systems including untouched rangelands, semi degraded rangelands due to grazing, rangelands that converted to rainfed agriculture, abandoned rainfed agriculture and an irrigated wheat farm in eastern Qazvin province, Iran. Samples were taken from the surface layer (A horizon) of soils in a completely randomized design with four replications. Statistical comparisons of the results revealed highest decrease in soil organic matter and total nitrogen owing to abandoned rainfed agriculture that showed 74% and 70% decline, respectively. Eventually the abandoned rainfed agriculture meets the sharpest slump in some soil properties such as cation exchange capacity (CEC), available phosphorous, total porosity and thickness of A horizon. Meantime the most increase in bulk density was also in recent land use. According to the results, the negative effects of inappropriate land use changes were led to soil productivity decline and will cause undesirable consequences in soil quality. So maintenance of soil quality is critical to environmental sustainability and this should be done on the basis of recognition all features that reduce its quality.
